ASoC: rsnd: dvc: make sure DVC soft reset

Renesas SCU (Sampling Rate Convert Unit) includes SRC/CTU/MIX/DVC,
and these have similar register. xxxRSR (Software reset Register) is one
of them. These xxxRSR need be set to 1 to 0 when software reset.
Current rsnd driver has src.c / dvc.c, and we will have mix.c.
It is readable if these have same named function.
This patch adds rsnd_dvc_soft_reset() and make sure it

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Keita Kobayashi <keita.kobayashi.ym@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sh/rcar/dvc.c

@@ -64,6 +64,12 @@ static const char * const dvc_ramp_rate[] = {
 	"0.125 dB/8192 steps",	 /* 10111 */
 };
 
+static void rsnd_dvc_soft_reset(struct rsnd_mod *mod)
+{
+	rsnd_mod_write(mod, DVC_SWRSR, 0);
+	rsnd_mod_write(mod, DVC_SWRSR, 1);
+}
+
 static void rsnd_dvc_volume_update(struct rsnd_dai_stream *io,
 				   struct rsnd_mod *mod)
 {
@@ -160,15 +166,14 @@ static int rsnd_dvc_init(struct rsnd_mod *dvc_mod,
 
 	rsnd_mod_hw_start(dvc_mod);
 
+	rsnd_dvc_soft_reset(dvc_mod);
+
 	/*
 	 * fixme
 	 * it doesn't support CTU/MIX
 	 */
 	rsnd_mod_write(dvc_mod, CMD_ROUTE_SLCT, route[src_id]);
 
-	rsnd_mod_write(dvc_mod, DVC_SWRSR, 0);
-	rsnd_mod_write(dvc_mod, DVC_SWRSR, 1);
-
 	rsnd_mod_write(dvc_mod, DVC_DVUIR, 1);
 
 	rsnd_mod_write(dvc_mod, DVC_ADINR, rsnd_get_adinr(dvc_mod, io));